Shock-absorber.



0. H. HAMMEBSMITH. SHOCK ABSORBER APPLIOATIOH FILED SEPT. 12, 1913.

1,1 1 3,61 9. Patented Oct. 13, 1914.

rdea, 7 WfJ/Em;

UNITED STATES PATENT OFFICE;

GHARLES H. HAMMERSMITH, 0F BROOKFIELD, ILLINOIS,

SHOCK-ABSORBER.

Specification of Letters Patent.

Patented Oct. 13, 1914.

Application filed September 12, 1913. Serial No. 789,414.

To all whom it may concern:

Be it known that I, CHARLES H. HAMMER- sMrrH, a citizen of the United States, residing at the village of Brookfield, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Shock-Absorbers, of which the following is a specification; I

M invention relates to improvements in shoe, absorbers and more particularly to.

to" com ress air therebetween to relieve the shock, ut wherein 'a supplemental yieldably movable part coacts with the compressed alr chamber, so that under extreme movement of thetwo elements, which are connected to the running gear and frame member respec- .tlvely, the air cannot be compressed to a suflicient extent effectively to transmit the shock, or brought under such-high pressure as to cause an unduly active recoil.

In the drawings '1 have illustrated one simple and efficientembodiment of my invention for purposes of full disclosure, but it will be understood by those skilled in the art that other forms of apparatus and details of construction may be employed for embodiment of my invention hereinafter claimed.

In the drawings Figure 1 is a central vertical cross section on line 11 of Fig. 2. Fig. 2. is a side elevation of a portion of an automobile chassis equipped with my in-.

vention.

A running gear element,typified as axle 10,and a frame element,.11, of an auto mobile are ordinarily interconnected by a suitable spring structure 12 for relative vertical movement. fundamental construction my present invention is not concerned but in'the exemplification shown the lower attaching stirrup 13' is assumed to be attached to the lower part With the details of such.

of the spring 12 and to the axle 10 as typifying any suitable connection of the lowerend of the shock absorber with a running gear element. Generally the upper stirrup construction 14 typifies any suitable connection of the upper end of the shock absorber with the body member to permit the desired movementbetween the upperand lower members of the shock absorber, 15 indicates a pneumatic shock absorbing I device comprising telescoping lower and upper members 16 and 17 which, as the lower piston member is forced into the upper cylinder member, may, compress air in a cylinder'chamber 18 inclosed by the twomembers. Specifically, member 17 consists of a cylindershell secured in the head 19 preferably having'intake ports 20 therein under laid, o-n the interior of the shell, by a flat flexible leather check-valve 21, or otherwise suitably equipped for outward closure to prevent the escape of air from chamber 18, and for inward opening to admit air there- I to. The coacting piston member 16 is preferably made also in the form of a hollow shell having a base 22 to which the stirrup 13 is secured, said base roviding a centralinternal boss 23, and said piston shell being provided at its upper end wit-h a transverse piston head 24! Manifestly with this construction, as the piston 16 is forced inward in cylinder 17, air is compressed in the chamber 18. Under normal load, or where the automobile is run ning on smooth surface, the device will stand with the air contained in chamber 18 but little above atmospheric pressure. Such a device responds to even slight shocks upon the running gear member by movement of the piston within the. cylinder, the air cushion serving to help absorb the shock and the device not materially lessening the lightshock absorbing capacity of the vehicle springs 12. Under heavier shocks, however, as Where the vehicle strikes an abrupt projection in the road, the relatively extended movement between the piston 16and cyl- V inder 17 tends to compress the air \in the chamber 18 to a high degree and the highly.

compressed air, of course, is less effective thereof to the vehicle body, although of course even under such conditions, and if the pistgn head 24 were solid, the device would best material aid to the springs 12 in absorbing the shock. However\for the princi\\ pal purpose of preventing undue compression of air within the chamber 18 under ex treme movement of the cylinder and piston parts whichare directly movable with the body and frame members, I provide, in communication with said chamber, a supplemental chamber part, one wall of which is yieldableunder the pressure of the air compressed in chamber 18, so that the yielding of said wall may prevent undue compression of the air in the chamber 18. In the specific'construction shown I preferably providesuch chamber, as at within the piston 16 and it isto this end that the piston is made. in the form of a shell, The piston head 24 is movable within said supplemental chamber in the shell, said head being itself constructed to provide a trunk piston part 27 and overlying flexible cup 28, a re inder taining washer 29 and a connecting bolt 30, having a nut 31 on the under side of the piston. The boss 23 and nut 31 serve to posi' tion axially a compressible coil spring 33, which actsiyieldingly to maintain the head 24 normally at its upper limit of throwv where its valve cup 25 presses against an annular valve rim 34 screwed into the upper extremity of the shell 16, so reducing to substantially naught the air receiving capacity of the supplemental chamber, It is my preference that thechamber 25 belowthe movable trunk piston '27 shall be provided with ports, as 35, for free entrance and exit of air, but, if preferred, said chamber may be made air tight throughout its walls, so that movement of the head 24 may compress air therein to afford gradually increasing 1' sistance supplementing the resistance of spring 33. r 1

In practice the spring 33 is made strong enough to resist the air pressure brought upon the trunk piston 27 of head 24 which is incident to the movement of piston 16 through a considerable range within the cyl-' 17, but it willbe manifest that when the movement of piston 16-, with the cylinder 17, is so great that the air in the now-reduced chamber 18 is'under pressure sufiicient to overcome the resistanceof spring 33, the supplemental piston 27 of main piston 16 yields against the spring; 33 thereby increasing the dimensions of the chamber 25 which communicates with chamber 18 directly and in this way preventingthe air under OOH]: pression in chamber 18 from being com-' pressed to such a degree as undulyto trans- ;mit shock from the running gear to the body;

Of course during restoration to their nor-.

mal positions the parts work in'just the ops vehicle running gear shell; a-movable posite fashion to that described, spring 33 bringing the supplemental piston 27 back to normal position as the air pressure in chamber 18 decreases and piston 16 as a whole moving outwardly to normal position in the cylinder 17.

Any sudden separation of the running gearand frame partslO and 11, due for 111- stance to the wheels following an abrupt depression in the path of travel, results in a sudden retraction of the piston 16, as a whole, which would tend to rarefy the air in chamber 18 and this results in the openng of valve 21 and the introduction of a quantity of air to maintain approximatelyatmospheric pressure in chamber 18.

Having described my invention, what I claim is 1. The combination with running gear and frame elements, of a pneumatic shock absorber comprising coacting chamber-forming parts relatively movable directly with the run ning gear and frame members for compression of the chambered air; a spring resisted yielding wall movable to said chamber under the action of the com pressed air therein, and an, inwardl ing check valve in the wall of said 0 open at its outer side to the atmosphere.

2. In a pneumatic shock absorber, inder; a piston therein, nection of said cylinder and piston with respectively, whereby frame members,'to which they are attachable, approach each other, said piston having therein a spring resisted yielding Wall open at its outer face to the atmosphere.

- 3. In a pneumatic shock absorber, a cylinder; means to connect it with one element of a vehicle; a piston in said cylinder; means to connect it with another member of the vehicle, said piston comprising a hollow shell; a supplemental piston positioned entirely within the last mentioned piston and reciprocable therein, yielding means opposing the movement of said supplemental pistonvwithin said piston shell'and an in wardly opening check valve being open to the atmosphere.

1. In a pneumatic shock absorber, a piston structure comprising a shell; a base for such piston head reciprocable in said shell; a stop for limiting the outward throw of said piston head with respect .to said shell; yielding means'norrnally maintaining said head against said stop; a cylinder coacting with said piston structure as a whole, said cylinder havinga ort therein and anon war'dly closing chec valx e for said .port, e outer side of said valve being open to the atmosphere. 7

.5. In' a pneumatic shock absorber, the

open-' amber and frame members" they may coact to compress air when the running gear and;

enlarge combination of a cylinder, a second cylintioned cylinder with its outer face open to .cler positioned with its open end telescoping the atmosphere. 10

within the open end of the first mentioned In testimony whereof I hereunfto set my cylinder, a piston slidable Within the second hand in the presence of two Witnesses.

cylinder, resilient means acting upon said CHARLES H. HAMMERSMITH. piston and normally holding the same in In the presence ofthe open end of its cylinder, and an in G. E. WOLF,

wardlyopening check valve in the first men- 0. A. THOMPSON.

fiopies of this patent may he obtained for five cents each, by addressing the Gommiss'ioner of IE'atents,

' Washington, D. G. 

